Public transportation and normal business operations resumed on Monday in Shenzhen, Guangdong province, after the city achieved a so-called dynamic zero infection rate of COVID-19 over seven days, sources in the local government said.

The city completed three rounds of citywide testing from March 14 to 20, and most new local COVID-19 cases were found in people already under quarantine.

"The COVID-19 pandemic situation in the city remains grim but generally under control," said Huang Qiang, deputy secretary-general of the Shenzhen municipal government.

Huang said the number of locally confirmed cases identified outside quarantined areas in Shenzhen had decreased from a previous high of 38 to a single case on Saturday, which meant the city had initially achieved "dynamic zero" status.

The city reported 44 new local cases, either confirmed or asymptomatic, on Sunday. Of those, 42 were found among quarantined people, the local health commission said on Monday.

Resumption of bus and metro services aims to achieve precision prevention and control of the pandemic and realize maximum effects at minimum cost, Huang said during a news conference on Sunday.

"It also aims to ensure the safety and stability of industrial and supply chains, as well as to allow local residents to resume their normal lives," he said.

Shenzhen will adopt a variety of measures for enterprises in industrial and supply chains to ensure stable operations, Huang said, adding that the city will continue to reinforce control and prevention measures in residential communities and villages, where negative test results within 48 hours are required for entry and exit.

Also, enclosed public service venues, student and child care institutions and in-person education and training institutions will remain closed.